1. Field of the Invention
The present invention relates to multilayer capacitors, and in particular, to a multilayer capacitor which is used in a high-frequency circuit.
2. Description of the Related Art
As a decoupling capacitor that is used in a power supply circuit for an MPU (micro processing unit) in a high-frequency range on the order of several GHz, a known multilayer capacitor is disclosed in Japanese Unexamined Patent Application Publication No. H11-144996. According to this multilayer capacitor, multiple terminals are provided and adjacent terminals have opposite polarities, so that currents from positive terminals to negative terminals are short and currents flow in various paths. Further, currents are caused to flow in opposite directions so that magnetic fluxes are canceled, and thus a reduced ESL (equivalent series inductance) is achieved.
However, according to the multilayer capacitor disclosed in Japanese Unexamined Patent Application Publication No. H11-144996, an ESR (equivalent series resistance) also decreases with decreasing ESL, which results in steep frequency-impedance characteristics.
On the other hand, Japanese Unexamined Patent Application Publication No. 2001-284170 discloses a multilayer capacitor in which for each internal electrode provided in a capacitor body to provide a capacitance, only one lead-out portion extending to the surface of the capacitor body and electrically connected to an external terminal electrode is provided, so that the ESR of the multilayer capacitor is increased.
However, according to the structure described in Japanese Unexamined Patent Application Publication No. 2001-284170, although an ESR can be increased, an ESL increases with increasing ESR. This causes degradation of high-frequency characteristics, as compared with the structure described in Japanese Unexamined Patent Application Publication No. H11-144996.
In addition, according to the multilayer capacitor disclosed in Japanese Unexamined Patent Application Publication No. 2001-284170, in the frequency-impedance characteristics, the resonance point is shifted to the low frequency side. Thus, there is no substantial difference from Japanese Unexamined Patent Application Publication No. H11-144996 in terms of a frequency band in which low impedance can be obtained, and thus it is not possible to increase the width of the frequency band in which low impedance can be obtained.